The goal of cancer immunotherapy is to elicit anti-tumor immune responses. Injecting tumor antigens for immunotherapy results in T cell responses that are weak and ineffective due to a lack of good adjuvants. Recent emphasis has been on pathogen associated molecular patterns (PAMPs) as candidate vaccine adjuvants. PAMPs are molecular signatures that define classes of microorganisms and induce potent immune responses. The long-term goal of the proposed studies is to understand the molecular mechanisms of activation of PAMPs on their receptors, Toll like receptors (TLRs). Modulation of TLRs and modification of PAMPs will greatly enhance cancer vaccine adjuvanticity thereby improving immunotherapy of cancer. In this grant period we will determine control mechanisms for PAMP recognition and receptor trafficking in a subfamily of Toll like receptors (3, 7, 8 and 9). These transmembrane Toll like receptors share the properties that they are not expressed at the cell surface and that they recognize nucleic acids such as dsRNA (TLR3), ssRNA (TLR7 and TLR8) and CpG containing DNA (TLR9). We hypothesize that nucleic acid recognizing Toll like receptors share localization, trafficking and PAMP recognition mechanisms that are controlled by discrete sequences in the cytoplasmic and ectodomains. We will test the hypothesis in two specific aims. First, we will determine the molecular mechanisms of localization and trafficking of nucleic acid recognizing Toll like receptors in response to PAMPs. Second, we will determine the specific binding regions on TLRs for the corresponding PAMP ligand. This information will fill gaps in the knowledge of Toll like receptor-PAMP biology: the molecular basis of ligand recognition, and the role of cellular targeting in controlling signaling. This information will allow the development of novel therapeutic strategies to modulate the immune responses to improve cancer vaccine adjuvants. This career transition grant will allow me to develop a research program focused on new ways to exploit TLR-PAMP biology for the treatment of human cancer.